Process of covering metal tubes with veneers.



No. 792,005. PATENTED JUNE 13, 1905. L. GOBURN.

PROCESS OF COVERING METAL TUBES WITH VENEERS.

APPLICATION FILED MAR. 29, 1905.

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UNITED STATES Patented June 13, 1905.

PATENT OFFICE.

LEMUEL COBURN, OF HOLYOKE, MASSACHUSETTS.

PROCESS OF COVERING METAL TUBES WITH VENEERS.

SPECIFICATION forming part of Letters Patent No. 792,005, dated June 13, 1905.

Application filed March 29, 1905. Serial 110.252,?05.

To all whom it nuty concern.-

Be it known that I, LuMUEL CoBUEN, a citi- Zen of the United States of America, residing at Holyoke, in the county of Hampden and State of Massachusetts, have invented new and useful Improvements in Processes of Govering Metal Tubes with Veneers, of which the following is a specification.

This invention relates to a process for covering metal tubes with veneers, the object of the invention being to provide an improved process whereby wood veneers, for example, which are very susceptible to moisture and expand quickly in the presence thereof, may be applied to metal surfaces, and particularly to metal tubes, in such way that when the veneers are dry and the adhesive material where-.

by they are secured to the tube has become set the meeting lines between the two edges of the veneer with which the tube is covered may be invisible and the veneer be separated from the metal by a tough slightly-yielding material to permit the metal and veneer to work more or less one relative to the other. I am aware that material like various pyroxylin compounds has been applied to metal tubes in the form of thin sheets; but this is adiiferent proposition, because of the fact that these compounds become plastic in the presence of heat, and the overlapping edges of a sheet of such material may be pressed together while in a plastic state to completely hide the point of their union. This amounts practically to melting the edges together to constitute an inclosing shell. I am aware that this mate- 'rial may be made to resemble wood veneer more or less closely, and thereby an article may be produced which externally would have the appearance of wood. The resemblance to wood, however, cannot be made so close as to deceive, and, furthermore, this material has always a very high polish, which is not always desired, and is highly inflammable. It is desirable, however, in various lines of manufacture, and especially in the manufacture of metal beds, to use steel tubing for strength and lightness, and to cover the same and for decorative purposes imitation wood veneers are usually employed. Another reason why the pyroxylin compounds have been preferred for covering metal surfaces is the fact that in a plastic state it is adherent to metal, whereas a wood veneer is not-that is to say, it is not so surely adherent as to make it possible to apply it directly to the metal with uniform success, and when so applied the non-adhering portions of the veneer will appear as blisters, and the veneer at such points becomes easily broken or chipped off. By means of my improved process, however, I am enabled to apply to metal surfaces a thin wood veneer and effect the adhesion thereof to the metal with uniform success, the veneer being so applied that in the finished article it is impossible to detect the meeting edges of the veneer.

The invention is fully illustrated in the drawings accompanying this specification, in which- Figure 1 is a perspective view of a piece of tubing having a covering of some pliable material, as paper, applied thereto. Fig. 2 is a perspective view of a piece of wood veneer which has been formed into tubular shape preparatory to applying the same to a papercovered tube, Fig. 3 is a perspective view showing the veneering applied to the tube with the edges thereof overlapped. Fig. 4 is a similar view to Fig. 3, showing the relation of the overlapping edges of the veneer after the latter has been secured by the process hereinafter described. Fig. 5 is a view like Fig. 4, but showing the finished veneer-covered tubing. Fig. 6 is a longitudinal sectional view of a receptacle in which pressure is applied to a veneer-covered tube inclosed in a constrictive water-tight container. Fig. 7 shows another means of applying constrictive pressure to the veneer-covered tubes. Fig. 8 is a crosssectional view of a veneer-covered tube after it has been allowed to dry under constrictive pressure.

In carrying out this process the tube a or other metal piece to be inclosed by the veneer is first covered with a strip of paper 6, by means of any suitable strong adhesive, as glue, and allowed to dry. The veneer c is cut in strips in the usual manner and moistened and rolled on a mandrel and allowed to dry, whereby it will assume the tubular form shown in Fig. 2, and preferably if a tube is to be covered the veneering is cut of such width only as is necessary to inclose the tube, each piece of veneer being rolled on a separate mandrel. The papered surface of the tube and the interior surface of the veneer are next covered with glue, the veneer being sprung open and passed over the tube, with the edges of the veneer overlapping, as shown at (Z, Fig. 3, and in this position the veneer is securely held in place by winding a string therearound; but the function of this fastening is merely to prevent the veneer from springing open, as it does almost immediately after the glue is applied thereto, because of the moisture contained in the latter. The veneer-covered tube is then inserted in an elastic container 0, a portion of which is shown in Fig. 4, and which is also shown in longitudinal section in Fig. 6, it being important that this container should lit the tube closely. This container preferably is a rubber tube having a closed end, into the open end of which a plug or stopper f is inserted to exclude water.

By inclosing the tube or other veneercovered article in an elastic container which lits the article closely (which container is afterward subjected to pressure) it is impossible for the veneer in drying to form blisters thereon, as it would be if the article were loosely inclosed in a container, for the reason that when the tube or other article in its container is placed in the receptacle (shown in Fig. 6) and pressure applied thereto in all directions all parts of the veneer will be equally pressed against the tube by the external pressure on the container. Preferably this pressure is applied by immersing the container in water which partly fills the receptacle, as shown, and then applying steam-pressure to the space above the water -level, whereby pressure in the presence of heat is applied in every direction to the container 6, thus pressing the veneer uniformly against the surface to which it is applied, and the elastic nature of the container will permit the veneer to shrink, as it does in drying, without relaxing in any degree the Contact thereof from the surface of the paper-covered tube on which it is practically thus shrunk on. Further more, the closely-fitting container permits pressure to be applied to the overlapping edges of the veneer, as at 7', Fig. 4:, so closely at all points that the overlapping edge of the veneer, softened by the hot glue, will be pressed in, as shown at Z, Figs. 4C and 8, and thus crowd the overlapped part in against the other edge underlying it, in such manner that when removed from the container this overlapping edge will stand out from the surface in the form of a well-defined rib, as shown in Fig. 8, and when this has been cut off and the veneered surface sand-papered the meetingline of the abutting edges of the veneer can scarcely be detected and after varnishing cannot be detected at all.

\Vithout the constricting pressure applied at all points to the veneering during the drying operation there would be no union between the overlapping edges which would not be at once apparent when the piece was linished, and it is only by applying such pressure in a way which will permit the natural shrinkage of the veneer during the drying process, without permitting the separation of the overlapping edge thereof from the underlying edge, that a perfect union of these edges can be effected, and it is on account of this contraction that it is impossible to make a butt-joint that will be invisible, and practicallyviz., commercially-irnpossible to attain the same end in a container in which the piece its loosely, for then there would be a fold in the wall of the container, which, if it should be located next to the overlap of the veneer, would leave the latter without pressure on that part.

In Fig. 7 another way of applying the req uisite constrictive pressure to the veneer during the drying operation is illustrated, and it consists in applying to the tube, as shown in Fig. 3, a thin metal shield at (illustrated in said Fig. 7) and winding the same from end to end with a cord 0, the purpose of the metal shield being to more uniformly distribute the constrictive effect of the cord and to prevent the indentation of the veneer by the cord.

It is important that some material be used between the wood veneer and the metal surface which shall be practically non-absorbent and yet having a body which in itself is strong enough to constitute a binder which will hold the veneer firmly against said surface when the veneer has shrunk into its final position. The best material I have found for this purpose is tough paper carrying suflicient sizing to render it practically non-absorbent. This interposition of a tough body between the veneer and the metal surface to which it is applied provides against danger of cracking the veneer and the separation thereof from the metal surface which would otherwise occur, owing to the fact that a properly-adhesive glue is very hard and brittle when dry. A textile material interposed between the veneer and the metal surface, for example, possesses all of the qualities desired except the non-absorbent characteristic, and if this be used the material takes up so much glue that when it is dry it becomes a hard brittle shell, because the glue penetrating all the fibers and then becoming dry destroys all the elasticity thereof, and it is much more liable to separate from the metal for the same reason that the wood veneer itself will spring away from it if applied without the intervening tough layer of paper, which permits the slight workingbetween the veneer and the metal due to the expansion and contraction of the two at different ratios of expansion.

Having thus described my invention, what I claim, and desire to secure by Letters Patent of the United States, is

l. The method of covering metal surfaces with wood veneer which consists in interposing a layer of practically non-absorbent material between the veneer and the metal and capable of being attached to both by means of a suitable adhesive.

2. The method of covering metal surfaces with wood veneer which consists in gluing a layer of practically non-absorbent material to the metal, then gluing the wood veneer to said material and subjecting the article to constrictive pressure.

3. The method of covering metal articles with wood veneer which consists in gluing a non-absorbent material to the metal then gluing the wood veneer to said material and inclosing the article in a constrictive casing and subjecting the casing to pressure in all directions.

4:. The method of covering a metal tube with wood veneer which consists in covering the tube with a sheet of non-absorbent material and gluing the same thereto and then applying a covering of wood veneer which extends around the tube and the edges of which overlap and then subjecting the tube to constrictive pressure by drawing an elastic casing thereover and applying pressure to the outside of the casing in all directions whereby the veneer will be held in yielding contact with the surface to which it is applied during the drying operation.

LEMUEL COBURN.

Witnesses:

GRANT J. AIKIN, ANDREW J. CHASE. 

